The present invention relates generally to displays which include a plurality of tiles, which are aligned to produce an image.
Previously when smaller array displays with separately addressable pixels are tiled to form a larger monolithic display, edge pixels of adjacent tiles had to be spaced at the distance of the pixels on each display tile; thus, adjacent tile edges must fall within the space between adjacent pixels. This space is small for high resolution displays and makes fabrication and assembly difficult and costly.
U.S. Pat. No 5,661,531 describes a tiling method for LCD displays where the adjacent edges of the tiles must fall within the space between adjacent pixels on the adjacent tiles. This space is a small fraction of the pixel pitch in either the x or y direction.
U.S. Pat. No. 5,056,893 describes a method where the adjacent pixels on tiled LCD displays are smaller than the non-adjacent pixels to allow more room for the adjacent edges of the tiled LCDs. The increase is space is only as large as the material removed from the adjacent pixels.
U.S. Pat. No. 5,673,091 describes tiled LCDs that are tipped at an angle and overlap adjacent tiles to eliminate interference of adjacent edges. Pixels of these LCDs are not on the same display plane, and the technique will only work with one row of tiled displays.
U.S. Pat. 5,903,328 describes tiled LCD displays where the adjacent tile edges are ground at an angle and overlap each other. This allows a small increase in the space for the ground edge relative to the adjacent pixels; however, as the space increases the distance between the image planes of adjacent tiles increases proportionally.
Small deviations in pixel uniformity are perceived by the viewer as defects in the display. Pixels must appear to the eye to be the same size and at the same plane across the tiles to provide a seamless display. In addition, pixels must maintain uniform periodic spacing, and uniform color and luminosity across the tiles to provide a seamless display.
It is an object of the present invention to provide an effective tiled display in which images, which are produced, are seamless to the viewer.
This object is achieved by a display, comprising:
a) at least two tiles which are aligned along one edge of each tile but are spaced from each other, each tile having electric field activatable pixels which produce light, each tile have said pixels spaced from their aligned edge; and
b) a back plate aligned with the two tiles and having electric field activatable pixels which are disposed so that they are positioned in the space provided between the aligned tiles whereby, when pixels on the two tiles and the back plate are activated, a seamless image is produced.
It is an advantage of the present invention that an image from a tiled display is seamless. This is accomplished by using the back plate to fill in pixels between spaced but aligned tiles.
It is a further advantage of the present invention that the increased space allowed between tiles reduces the accuracy requirement for tile placement. Furthermore, the requirements for tile edge finishing are less constrained.
The present invention is particularly suitable for use in organic electroluminescent displays. A feature of the invention is that it can be readily manufactured and the display will not produce artifacts caused by aligned tiles.